Calculating profit maximizing output level in the given case

The El Dorado Star is the only newspaper in El Dorado, New Mexico. Certainly, the Star competes with The Wall Street Journal, USA Today, and the New York Times for national news reporting, but the Star offers readers stories of local interest, such as local news, weather, high- school sporting events, and so on. The El Dorado Star faces the demand and cost schedules shown in the spreadsheet that follows:

a.How many papers should be sold daily to maximize profit?
b. What is the maximum profit the El Dorado Star can earn?
c. What is the total fixed cost for the El Dorado Star? If the total fixed cost increases to $5,000, how many papers should be sold daily for profit maximization?